It's part of a quantum course, but the problem I'm having is pretty straight math.

There are two similar functions I need to square. I can do it fine, but the question calls for 'simplified form' and I'm struggling to simplify.

They are $\displaystyle 1-e^{-iat}$ and $\displaystyle 1+e^{-iat}$. Take the subtraction example (the only difference with the other one is a sign): I get $\displaystyle 1-2e^{-iat}+e^{-2iat}$.

Is there a way to express this more simply?